Pernicious anaemia is an autoimmune condition that causes your immune system to attack the cells in your stomach, preventing your body from absorbing vitamin B12.
But despite being given supplementation, his B12 levels remained low – ruling out pernicious anaemia as a cause.
Exposure to nitrous oxide in his workplace was actually established to be the cause.
The study explained: “In conjunction with previously reported cases of B12 deficiency in health care workers due to exposure to nitrous oxide, possible role of chlorofluorocarbons and other freon gases was hypothesised especially in the light of his occupation.